1. Field of the Invention
The present invention relates to an integrated circuit including a dielectric line of the type comprising a dielectric strip disposed between two parallel conductor planes.
2. Description of the Related Art
Circuits using a dielectric line, in which electromagnetic waves propagate along a dielectric strip inserted between two parallel conductor planes, have been developed as integrated circuits for use in a microwave band or a millimeter-wave band. When such a dielectric line is formed, various types of construction have been adopted. For example, an oscillator, a circulator, a mixer or the like may be formed as a module and such modules may be placed in a predetermined positional relationship, thus forming one integrated circuit. Or, several circuit elements may be arranged between two conductor plates and integrated to form a single integrated circuit.
With the above-described constructions, in a conventional dielectric line circuit, the circuit elements are disposed within nearly the same plane in order to form one integrated circuit. Therefore, if the scale of the entire circuit is increased, the entire circuit is enlarged along the plane direction and thus will have a larger area. By providing the circuit with a multilayer structure, reduction of the area is possible; however, in the conventional technology, it is not possible to cause electromagnetic waves to propagate through the dielectric line in a direction vertical to the conductor plate of the dielectric line.
FIG. 16 is a schematic cross-section of a dielectric line circuit with a multilayer structure showing one attempt that has been made to address these problems. In FIG. 16, reference numerals 60, 61, 63 and 64 each denote a conductor plate. Dielectric strips indicated by reference numerals 62 and 65, each provided between two conductor plates, form two dielectric lines in this example. The end portions of the dielectric strips 62 and 65 are formed into a tapered shape, and further, the end portions of the conductor plates 61 and 63 are also formed into a tapered shape, to form an interface between the dielectric line and a waveguide 66. Thus the upper dielectric line and the lower dielectric line are connected by the waveguide 66.
However, as shown in FIG. 16, in a multilayer structure, wherein a dielectric line is connected to a hollow waveguide, problems arise in that large dimensions along the interlayer direction (thickness direction) are required, and further, a space is required in the conversion section between the dielectric line and the waveguide, so a small overall size cannot be achieved.